ITV News Political Correspondent Carl Dinnen has more on the restrictions in place to limit the spread of variants - and how long the measures will be with us
Two new homegrown variants of Covid-19 have been identified in the UK, both containing a mutation found on the Brazilian and South African strains.
One of the new variants, first identified in Bristol, has been designated a "variant of concern", by the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG).
The other, first identified in Liverpool, has been designated as a "variant under investigation" by the group.
Public Health England has a "high degree of confidence that the vaccines will work against variants", including the Bristol variant of concern.
Some 76 cases of the two new strains have been found so far in the UK.
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Of the fast-spreading Kent variant, there are now 51,550 cases, with an additional 8,116 since the previous update five days ago.
There are at least 170 cases of the South African variant in the UK, including 18 that are not linked to travel, with an increase of 19 since the last update on February 4.
Dr Susan Hopkins, from Public Health England, said: "To date we have identified 170 cases and 18 of these are unlinked to travel, and that means that they neither travelled abroad themselves or a direct contact with an individual that has travelled."
Of the Brazilian variant, 24 cases have so far been identified.
There had been concerned earlier in the week that the Oxford/AstraZeneca vaccine was less effective at stopping people becoming mildly ill from the South African variant.
The study into the mutation known as E484K involved some 2,000 people, most of whom were young and healthy.
Oxford vaccine lead researcher Professor Sarah Gilbert said that the current vaccines “have a reduction in efficacy against some of the variant viruses.”
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She added: “What that is looking like is that we may not be reducing the total number of cases but there’s still protection in that case against deaths, hospitalisations and severe disease.”
Prime Minister Boris Johnson sought to reassure the public, saying he is "very confident in all the vaccines that we're using" because they all protect against severe illness and death.
The UK is still keen to block the arrival of foreign variants, and on Tuesday announced a tightening of border controls to reduce the risk of a new strain being brought to the UK and interfering with the vaccine rollout.
While the government wants to block further arrivals of foreign variants to the UK, Deputy Chief Medical Officer Jonathan Van-Tam says it's unlikely the South African strain will become the dominant in the coming months because it does not enjoy "transmissibility advantage" over other variants.
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It's been reported that a third 'top-up' dose of coronavirus vaccine may be necessary in the future if variants mutate to escape current vaccines.
In a drive to vaccinate the four groups most vulnerable to coronavirus, over-70s who have not yet been offered a Covid jab are being encouraged to contact the NHS to arrange an appointment.
It comes with the government just days away from saying whether or not it has met its target for offering all people in the top four priority groups a Covid jab before the middle of February.
The latest figures show 12,646,486 people have been given a first dose of a vaccine.
Health Secretary Matt Hancock said that means 91% of over-80s and and 93% of eligible care home residents have had their first dose of the vaccine, 95% of those aged 75-79, and almost three quarters of those aged 70-74.